Tuesday, November 25, 2008

Bit and pieces

Lately time to work on the boat has been scarce with the holidays upon us and other commitments. Nevertheless a little progress has been made, lately. In an effort to stiffen up the largely flat sections in the aft two compartments, I glassed in some structural members half way between the chine and the rail. Between f124 and f169.5 I tried encasing half of a piece of foam pipe insulation in two layers of biaxial. It ended up looking good, but only stiffened the panel a little bit. Not enough surface perpendicular to the hull panel, I think. Based on that result I glassed in a ~2" wide strip of plywood into the aft-most section---rock solid. I may go back and grind out the foam half-round, but there is a lot more to do in the short term. We'll see...

I also glassed in a sort of sheer clamp along the transom. The 3/4"x3/4" poplar ripped in the diagonal will provide a little more than an inch of surface to glue the deck down which will be good since I won't be able to tape back there.
My main focus is working on the keel. The handheld electric planner I bought has worked a treat thus far. I just requires the patience to only take off a little at a time. Get too aggressive and you will have many evening alternating between filling and fairing! I also got a 30" longboard that has been great to fine tune the shape. I bought a flexible longboard which will come in handy for fairing the hull, but modified to to make it rigid for fairing the keel. At $50 ea. for the rigid and flexible longboards, the modification was a good solution. I will post a pic when I can.

Sunday, November 9, 2008

The Keel Deal

Over the last few days Traci and I got all of the bunk supports filleted and taped.

The supports are now ready for the bunks...except for one minor detail: The keelbox. And since the keel is not done yet, neither is the keelbox. So I finally bit the bullet and started working on the keel...so that I can create the keel sleeve...so I can build the keel box...so I can install the aforementioned bunks. Seriously, if you builders are waiting on something like kit delivery, get started on the keel!

I used the Gougeon Bros. white paper on foil construction as a guide to fabricating the foils, with a few minor deviations.

Using the table saw I ripped lengths of cedar 2x10 to the desired thickness of the foil (~1.62" for a NACA0012 foil mius the thickness of a couple of layer of glass). After rotating them 90 degrees to get the grain running perpendicular to the foil chord and flipping every other one end-for-end, I laminated them together with thickened epoxy. Using a handheld electric plane I got the rough shape of the keel.

A few more passes with the plane evened out the "steps" shown above and the foil was really starting to take shape.

I've got a longboard on order, so I should be able to get the final shape faired and ready for carbon fiber reinforcement and glass sheathing later this week. Then more fairing to the get the final shape.

All in all, everything is coming along quite well.

Saturday, November 1, 2008

Under Pressure

As I mentioned in my previous post, I discovered that if the hull sides are stitched in tight to several of the frames the result will be a hollow around each frame. The hollow will ultimately require substantial fairing once the hull is flipped. More importantly, however, is that it takes a tremendous amount of force to pull the hull in tight to these frames. To me, it seems that pre-stressing the hull in this manner is not a good idea. I, for one, do not want my hull to contain substantial potential energy while it sits idle. After all, potential energy is what give bombs their power, right? I would worry that a minor collision in the area of a pre-stressed area could result in a substantial repair.

As an alternative I left the hull relaxed at these frames (all but 18 and 169.5). See pics below. I stitched the chine side and the rail side in tight and then transferred the curve of the hull section to a 2" wide piece of plywood. The 2" piece of plywood was sistered to the forward side of each frame with silica-thickened epoxy.

The "gap" on the aft side of the frame was filled with silica thickened epoxy and filetted as normal. One trick: the inboard side of the of the sister piece was beveled at 45 degrees to allow the glass tape to conform.